Apparatus for manufacturing alkali cyanid



F. J. METZGEH. APPARATUS FOR MANUFACTURING ALKALI CYANID. APPUCATION FILED JULY 25, 1917.

1,358,383, Patented Nov. 9,1920.

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UNITED. STATES PATENT OFFICE.

FLOYD J METZGER, OF NEW YORK, N. Y., ASSIGNOR TO AIR REDUCTION COMPANY, OF

- NEW YORK, N. Y., A CORPORATION OF NEW YORK.

I Specification of Letters Patent.

Patented Nov. 9, 1920.

Application filed July 25, 1917. Serial No. 182,645.

To all whom it may concern Be it known that I, FLoYn J. Mn'rzcnn, a citizen of the United States, residing in New York, county of New York, State of New York, have invented certain new and useful Improvements in Apparatus for Manufacturing Alkali Cyanid, of which the following is a specification.

In the construction of retorts or furnaces for the manufacture of alkali metal cyanid involving the treatment of a mixture of alkali metal carbonate or alkali metal hydroxid and carbonaceous material with nitrogen or nitrogen-containing gas, a number of difficulties have been encountered. The chief difliculty met with has been the difiiculty of so constructing the furnace that the retort or furnace would withstand the alkali metal compounds on the one hand and on the othei thehigh temperature required to cause the necessary reactions between the nitrogen and the in redients of the mixture to produce the pro not desired, viz. alkali metal cyanid.v

If the retort or container for holding the mixture be made of iron-and subjected to the usual oxidizing furnace gases at the high temperature required its life is comparatively short. In such case the item of expense for upkeep is one of considerable importance. i

One of the principal objects of my invention is to provide a construction in which the metal retort for containing or holding the mixture, to be treated shall be maintained in an inert atmosphere such as nitro- By roviding such a construction I am enabled to. increase (to a ver great extent) the life of or the length time during whichsaid retort may be used. In consequence of this the cost of producing the alkali metal cyanid isvery much lowered or decreased. A A further-object of, my invention is to provide a' convenient, "practical and relatively inexpensive form of. furnace which obviates the difliculties above pointed out and which renders feasible the manufacture of alkali cyanid by a method in general accordance with that above mentioned.

Other ob'ects and advantages of my invention will be referred to and pointed outin the detailed description thereof which follows 'orwill be apparent from such descrlption.

In order that my invention may be more.

readily understood and the practical ad- Fig. 2' is a transverse section of the retort,

taken on the line 2-2 of Fig. 1.

Referring to the drawing, ,1 designates the walls of the furnace construction, the chamber of which is providedat its lower-portionv with grate bars 2, or other suitable means, for supporting the bed of fuel employed for heating the furnace! It will be understood that any other desired suitable and known means may be employed for heating the retort within which the reactions in the manufacture of the cyanid-take place.

3 designates an opening in the furnace wall through which the fuel is charged into the furnace, and 4 designates an openin through which ashes, etc., may be remove The-gases of combustion escape from the furnace chamber 6 to an outlet at 7.

Extending across and through the .fur-

n'acechamber 6 a short distance below the top thereof is a retort 10 preferably of D- shape and of refractory material, such as silica or fire clay. "This retort; is secured a and supported in openings irf'opposite'wallsv 1 of the furnace and it ends project somcwhat beyond these wal1s, ass 1 of the drawing.

Situated within n... retort 10 and sup-- ported therein so that it is spaced at all points from the inner surface of the retort 10 is a second retort 11' of metal. such as iron. 1 his retort also is of D-shape, as is likewise shown in Fig. 2 of the drawing. It

own in Fig.

will be understood that my invention is not limited to retorts of any particular shape or contour.

The metal retort 11 is supported upon collars 12 secured to the opposite ends of the retort 10. These collars are respectively providedwith openings 13 through which the opposite ends of the said retort 11 extend. The said retort 11 fits closely within the said openings 13 so that the chamber 11 intermediate the two retorts is air or gas tight. The opposite ends of the retort 11 project a short distance beyond the respective disks 12.

These retorts are shown as occupying slightly inclined positions, -but it will be understood that they may occupy other positions, even horizontal positions if desired.

The opposite ends of the retort 11 are closed by means of heads or covers 15 and 16.

The charge consisting of a mixture of car- Y bonaceous material and an alkali metal compound such as carbonate or hydroxid is first charged into the hopper 17 which has connection through the tube 18 with the'in terior of the upper end portion of the retort 11, as shown. The said mixture passes downwardly through the tube 18 onto the bottom of the retort 11 and may be spread out uniformly thereover by means of a rake or other suitable means inserted through the openings 20 and 21 provided in the closing heads 15 and 16. Both of these openings, 20 and 21, are normally closed by means of closing doors 22. During the operation of the apparatus a portion of the mixture of carbonaceous material and alkali metal compound should remain in the hopper 17, filling the pipe 18 and maintaining a constant head therein, thereby sealing ofi' the apparatus.

The nitrogen'to be introduced into the re tort 11 and caused to react therein with the Fig. 1. The gaseousnitrogen so introduced travels around and forwardly and upwardly in the said chamber 11 becoming distributed entirely around the said retort 11- and finally enters the same through an opening 25 upon the upper side thereof at a point preferably considerably beyond its longitudinal center.

Assuming that the furnace is in a heated condition it will be understood that the nitrogen in its passage through the chamber 11 is preheated by the heat of the furnace before it enters the retort 11.

- After entering the said retort it is disciently high to cause the necessary reactions to take place between the nitrogen and the ingredients of the mixture constituting the charge alkali metal cyanide is formed.

By introducing the nitrogen gas or nitrogen-containing gas into the chamber blank surrounding the retort 11 it will be apparent that the said retort becomes completely surrounded by an inert gas so that the said retort is protected against the oxidizing action of the furnace gases or other deteriorating action.-

When the mixture constituting the charge in the retort 11 has been treated sufficiently to effect a completion of the reactions required to produce the product desired the said charge is drawn out of or removed from the furnace through the pipe 28 and is discharged into the receiver 29. After the treated charge has been removed a fresh charge is introduced into the retort 11 from the hopper 17 through the tube 18 and is spread out uniformly over the bottom of the said retort, as already described and the operations are repeated.

The nitrogen gas which remains uncon; Verted in the retort 11 together with the gaseous reaction products pass from the said retort throughthe pipe 28 into the receiver 29 and thence outwardly through the tube 30.. The latter is adapted to be closed bymeans of a valve at 31.

entering or leaking into the said retort either during the charging of the same or during the time that anyone of the openings 20, 21 or 32 may be opened. It follows that the valve at 31 should be closed at such times, particularly when the retort is raked, in order that the flow of gases may be outward from the inside of the retort.

The passage of the nitrogen gas from the retort 11 into the receiver 29 and thence outwardly through the tube 30 has the effect of maintaining the treated product which may be discharged into the said receiver in an atmosphere of inert gases thereby preventing decomposition of the cyanid which has been formed in the said retort.

It will be understood that in operating the apparatus as described other methods of procedure than that described maybe employed. For example, a mass of granular coke or other carbonaceous material properly impregnated with a catalytic substance (as finely divided iron) may be spread over the bottom of the furnace and molten caustic soda or sodium carbonate allowed to percolate slowly down through the mass, without, however, carrying the carbonaceous material along with it. In such case the outlet pipe 28 should be set back into theheated portion of the retort in order to prevent freezing or solidifying of the molten material and thereby obstructing the flow.

It should also be understood that changes in the details of arrangement may be made and that a plurality of retorts may be employed, such retorts being set up in series in a way similar to that in which benches of coal gas making retorts are set up. In

other words, the retorts may be duplicated and connected together in series. In such case the nitrogen employed may pass or travel successively through several or all of the retorts ina series, The several retorts may be connected together in sired known manner.

It will be seen that I have provided a construction of apparatus for the manufacture of alkali cyanid which is very simple and in which means is provided whereby the metal retort is maintained at all times within and surrounded by an inert gas, nitrogen, which protects the said retort from the deteriorating action and influences of the furnace gases as well as from other deteriorating action which might take place were the retort not so protected.

inner retort, means'for introducing a chargeof material intothe inner of said'retorts and means for supplying a gas to the cham-- ber intermediate the said retorts which gas spreads out and surrounds the portion of the said inner retort whichis situated within the outer retort and the said inner retort havingan opening therein to permit the entry of said gas into the same.

2. In apparatus for the manufacture of alkali ,metal cyanid by the treatment of a mixture of carbonaceous material, an alkali metal compound and nitrogen gas, the combination of a retort for'receiving the said charge, a wall of refractory material surrounding the said retort and being spaced at all points therefrom so as toform a cham- L ber entirely surrounding the portion of said retort within the re "on of the said wall of refractory materia means carried by the 1 said wall of refractory material for supporting the said retort, means 'for supplying nitrogen gas or nitrogen-containing gas to anfber surrounding the said retort at or near one e'nd of the said chamber, the said retort being provided with an opening any .de-

gen-containing gas into the said chamber whereby the said nitrogen is caused to travel a relatively great distance through said chamber before entering the said retort and the said nitrogen being thereby preheated by the heat of the furnace; a receiver for receiving from said retort the gases present and also the charge after the latter has been treated within the said retort and means for conveying the said gases from the said receiver.

3. In apparatus for the manufacture of alkali metal cyanid by heating a mixture of carbonaceous material and an alkali metal compound, in the presence of nitrogen gas, the combination of heating means,

a retort of refractory material to which the heat is directly applied, 'a retort of metal extending through the first named retort and being spaced at all points therefrom to form a chamber intermediate the said retorts, means for introducing a mixtureof carbonaceous material and an alkali metal compound into the second named retort, means for supplying gaseous nitrogen to the said intermediate chamber at a point at or near one end thereof, and the said second named retort having an opening therein through which said gaseous nitrogen may pass thereinto, said opening being situated a relatively great distance from the point of introduction of the said gaseous nitrogen into the said chamber whereby the said gaseous nitrogen may be preheated sufiiciently before it enters the said retort and means twhereby said charge, after it has been properly convertedto produce alkali'metal cyanid, may be' discharged from the second named retort.-

4. In apparatus for the manufacture of alkali metal cyanid by the heating of a mix-t ture including carbonaceous material and an alkali metal compound 1n a hot retort 1n the presence of nitrogen gas, in combination, a

furnace, a retort of refractory material ex tending through said furnace and adapted to be, heated to the temperature desired, an iron retort extending through the said re fractory, retort and being supported in spaced relation thereto so as to form achamvber within the said refractory retort and entirely surrounding the portion of the said tainin gas enters the said retort, a receiver v I into w 1ch the converted mixture within the said metal retort is discharged after the riceessary reactions have taken place therein, the said receiver having connection with the said metal retort at a point adjacent the end of said retort opposite that at which the char e is delivered to said retort.

5. n apparatus for the manufacture of alkali metal cyanid, the combination of a retort of refractory material, a metal retort extending through and having its opposite ends project through the opposite ends of the said refractory retort, the said refractory retort being spaced from the said metal retort in order to provide a chamber extending entirely around the said metal retort, the said'metal retort having an opening therein whereby the said chamber is in communication with the interior of said retort, means for discharging a mixture of carbonaceous material and an alkali compound into a pro jecting end of said metallic retort, means for delivering a nitrogenous gas to the said chamber which gas fills the said chamber and entirely surrounds the portion of the said metal retort within the said refractory retort, means for heating the said retorts, the gas within the said chamber being thereby heated before it enters the opening into the said metal retort, a receiver having connection with the projecting end portion of said metal retort opposite that at which the charge of said mixture is delivered to said retort, and means for conveying the said gas from said receiver.

6. In an apparatus for the manufacture of alkali metal oyanid, the combination of a retort of readily oxidizable metal, a surrounding wall of oxidation resistant material spaced from said retort to form a chamber, means for maintaining an inert gaseous atmosphere in said chamber and means for heating said retort by the application of heating gases to said surrounding wall.

7. In an apparatus for the manufacture of alkali metal cyanid, the combination of an iron retort, a surrounding wall of an oxidation resistant material spaced from said retort to form a chamber, means for maintaining an inert gaseous atmosphere in said chamber and means for heating said retort by "the application of heating gases to said surrounding wall.

In testimony that I claim the foregoing as my invention, I have hereunto signed my name this 23 day of July, A. D. 1917.

K FLOYD J. METZGER. 

